Sunday, February 21, 2016

And You'll See Armadillos Gallop To New Mexico

Credit WHO SitRep Report


The above title is an example of a Mondegreen - or a misheard lyric - in this case from Bobby Troup's immortal (Get Your Kicks) On Route 66.  The real lyrics are `You'll see Amarillo and Gallup, New Mexico'.

And I'll confess that as a 3 year old, I thought Patti Page sang `leave your pickle patch behind you' in order to `Crossover the bridge'.  But I digress . .

Unfortunately, this sort of malapropism extends well beyond hilariously misheard lyrics, it also shows up as (accidentally or deliberately ) misinterpreted `reporting' on scientific studies, and through the power of the Internet's echo chamber, often gains a life of its own. 

Case in point.  On Friday the World Health Organization's Zika Open page published a study called:

Update on Zika virus transmission in the Pacific islands, 2007 to February 2016 and failure of acute flaccid paralysis surveillance to signal Zika emergence in this setting
- Adam T Craig, Michelle T Butler, Roberta Pastmore, Beverley J Paterson, David N Durrheim
Posted: 19 February 2016

This morning, in doing my normal Google searches, I ran across several websites citing this study - and after cherry picking a few sentences (and taking them out of context) - heralds the study as finding `no link between the Zika virus and Guillain-Barre syndrome'.

While suspected, the link between Zika virus infection and Microcephalic births and rare cases of Guillain-Barre syndrome remains unproven. And even if Zika is ultimately implicated as the cause of one or both, there may well be other co-factors involved.

All important caveats.  But to suggest that this study somehow proves there is `no link' between Zika and GBS, is well . . . misleading at best. 

So this morning, a quick look at this study, and what it actually found. 

The intent was to see if increased rates of AFP (Acute Flaccid Paralysis) in children < 15 years - which is well monitored as part of the global polio eradication effort - could be used to infer Zika virus outbreaks in the South Pacific in areas where testing has not been done. 

By examining published and unpublished accounts of AFP since 2007, they hoped to find evidence of - as yet - unidentified outbreaks of Zika among Pacific Islanders. 

What they found was the quantity and quality of available data on AFP in the Pacific was too sparse to make it an effective indicator of hidden Zika outbreaks.  They wrote:

`While we found this strategy was not effective in Pacific islands countries where populations are small (and hence expected number of AFP cases is low, often less 1 per year) and surveillance data quality inadequate, we suggest that the utility of this surveillance strategy be explored in countries vulnerable to Zika transmission and that have large populations under 15 years of age.'

In their conclusion, they summed up their findings:

`We found no spatial-temporal correlation between routinely collected AFP data and ZIKV emergence in previously unaffected Pacific island countries. '

They go on to suggest the idea still has merit, and should be tried elsewhere.

How exactly one reads this study, and comes away with a `Study Finds No Correlation Between Zika and GBS' headline, eludes me.

But then, I never saw galloping armadillos when I last visited New Mexico, so I suppose the fault could be mine.